Is the sound from the warning alert system?

The video here is of footage of a man driving a train. There is a beep at 4:40 and the driver seems to do something in response to it. Could the sound be from the warning alert system? Is there any way to be sure about this?
The alert system is a system designed to check that the drive is alert and able to operate the system effectively.
http://www.youtube.com/watch?v=_xLgY7pCkak